Casmir was the son of the king of Poland. As a young man he led an extremely austere life. He slept on the floor, spent copious time in prayer and committed himself to celibacy.

When the nobles in Hungary became dissatisfied with their king, they asked Casimir’s father to send his son to take over the country. Dutiful to his father, Casmir and a portion of the Polish army went to that country. His army, however, was clearly outnumbered by its enemies. Some of his troops deserted because they were not paid. At the advice of his officers, Casimir decided to return home.

Casmir’s father became so angry at the failure of his plans, that he confined his 15-year-old son for three months. Casmir made up his mind never again to become involved in the wars of his day, and no amount of persuasion could change his mind. He returned to prayer and study, maintaining his decision to remain celibate even under pressure to marry the emperor’s daughter.

Casmir only reigned briefly as king of Poland during his father’s absence. He died of lung trouble at 25 while visiting Lithuania, where he also was grand duke. He was buried in Vilnius, Lithuania.

Adapted by A. J. Valentini from: St. Casimir | Franciscan Media. (n.d.). Franciscan Media. Retrieved Feb. 25, 2021, from